Explorium vs Apollo.io vs Hunter.io

Objective, side-by-side analysis of Explorium, Apollo.io, and Hunter.io to help you evaluate features, pricing, and performance and find the perfect fit for your data needs.

Explorium

4.8

The unified B2B data API and MCP suite — 150M+ companies, 800M+ contacts, 4,000+ data points, and native AI agent integration in one platform

  • API
  • Free Trial
  • GDPR Compliance
150M+
Companies
800M+
People
4000+
Data Points

Selected Customers

Clay • Common Room • Cognism • Outreach • Bombora • Monday.com • Artisan

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Apollo.io

4.7

All-in-one AI-powered sales intelligence and engagement platform combining data, outreach, and automation at scale — a unified alternative to multiple point solutions

  • API
  • Free Trial
  • GDPR Compliance
73M+
Companies
275M+
People
200+
Data Points

Selected Customers

Autodesk • DocuSign • Customer.io • Census

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Hunter.io

4.4

The original email finder and verifier — simple, accurate, and trusted by over 6 million professionals

  • API
  • Free Trial
  • GDPR Compliance
76M+
Companies

Selected Customers

Google • IBM • Microsoft

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Primary Use Cases

Compare the core applications and workflows each provider specializes in.

Explorium

  • GTM Agents

    Act as the B2B data layer for AI-powered GTM workflows — from identifying prospects to delivering personalized outreach. Supports MCP-native access via Claude and other AI agents.

  • ABM Targeting

    Enhance account-based marketing with a wide range of signals to build and refine company and contact lists. Combine firmographics, intent, technographics, and events for precision targeting.

  • AI Recruiting

    Build recruiting automation systems on top of a premium B2B data layer. Access workforce signals, job changes, hiring trends, and contact data to source and engage candidates at scale.

Signals powering these use cases

  • Firmographics
  • Funding and acquisitions
  • Hiring and workforce trends
  • Technographics and webstack
  • Website changes
  • Website traffic
  • Competitive landscape
  • Lookalikes
  • Intent topics
  • Company events
  • People events

Apollo.io

  • AI-Powered Prospecting

    Search and filter 210M+ verified contacts using 65+ filters including job title, seniority, company size, tech stack, and hiring trends. AI identifies and prioritizes best-fit prospects automatically.

  • Multichannel Sales Engagement

    Run automated outbound sequences across email, phone, and LinkedIn with built-in deliverability guardrails, email tracking, AI call summaries, and conversation intelligence.

  • Data Enrichment & Lead Routing

    Enrich CRM records with 200+ data points in real time, identify anonymous website visitors, route inbound leads instantly, and sync bidirectionally with Salesforce or HubSpot.

Signals powering these use cases

  • Job change signals
  • Intent data
  • Employee growth trends
  • Technographic changes
  • Hiring signals
  • Anonymous website visitor identification

Hunter.io

  • Email Discovery

    Find professional email addresses for any domain or individual using Hunter's indexed database of 76M+ websites and public sources.

  • Email Verification

    Verify email deliverability before sending with multi-step checks including SMTP validation and confidence scoring to reduce bounce rates.

  • Cold Email Campaigns

    Send personalized cold email sequences directly from Hunter with built-in scheduling, follow-ups, and tracking for opens, clicks, and replies.

Signals powering these use cases

  • Domain-level email pattern detection
  • Public web indexing of 76M+ websites
  • Confidence scoring on every email found
  • Email verification with SMTP checks

Snapshot

Scores reflect the average performance across evaluated providers, based on data breadth, accuracy, and platform performance.

Explorium Snapshot

  • Company coverage 3.5
  • Signals depth 5.0
  • Freshness 1.8

Apollo.io Snapshot

  • Company coverage 2.1
  • Signals depth 3.5
  • Freshness 3.5

Hunter.io Snapshot

  • Company coverage 4.7
  • Signals depth 1.5

Detailed Feature Comparison

Side-by-side analysis of Explorium, Apollo.io, and Hunter.io across data coverage, platform capabilities, and technical specifications.

Feature Comparison
Explorium
Apollo.io
Hunter.io
Data Enrichment
ML Discovery
API Access
REST JSON API with batch support (up to 100 entities), webhooks, sync/async; up to 100 QPS; 99.999% uptime
REST API on all plans; 50–200 calls/min by tier; docs at docs.apollo.io
Full RESTful API; no premium plan required to use API
SLA
Up to 99.999% uptime; rate limit 200 requests/min per key
24-hour RTO/RPO; quarterly audits; annual third-party penetration testing
Near 100% uptime
Compliance
GDPR, SOC 2, CCPA, ISO 27001
GDPR, SOC 2 Type II, ISO/IEC 27001, CCPA; CASA compliant
GDPR and CCPA compliant
Custom Entities
-
Real-time Lookups
Global Coverage
150M+ companies and 800M+ contacts across 150+ countries
210M+ contacts globally; strongest in North America
Global with strongest coverage in US and Europe
CRM Integration
Available on custom enterprise plans
Bidirectional sync with Salesforce, HubSpot, Zoho; bulk invite and field mapping supported
Salesforce, HubSpot, Pipedrive, Zapier
Platform interface
REST JSON API, MCP server (AgentSource MCP), batch support up to 100 entities, webhooks, sync and async modes
Web application (SaaS), Chrome extension for LinkedIn prospecting, REST API
Web app, Chrome extension, API
Natural language search
Workflow automation
Automation integrations
n8n, Claude, custom webhook integrations
Zapier, Intercom, Zendesk, ServiceNow, Klaviyo, Salesloft, Outreach
Zapier (5,000+ endpoints)
Company coverage
150M+ company profiles
30M+ company profiles
76M+ websites indexed for email pattern detection
People coverage
800M+ people profiles (767M+ verified contacts)
210M+ contact records
Millions of professional email addresses across US and European markets
Geographic coverage
150+ countries
Global; strongest in North America; international accuracy lower outside the US
Global, with strongest coverage in US and Europe
Data sources type
50+ data providers; proprietary ML enrichment; real-time web signals
Proprietary 2M+ contributor network, public web crawling, engagement suite signals, vetted third-party data providers
Publicly available web pages, company websites, press releases, social media profiles
Global schema consistency
Unified schema across 4,000+ data points globally; consistent API response structure
Consistent schema with 65+ filters and 200+ fields globally; accuracy varies by region
Consistent email + confidence score schema across all records
Refresh frequency
Daily for high-velocity signals; weekly for semi-dynamic attributes; monthly/quarterly for stable firmographics
Real-time when data signal captured; 150M contacts refreshed monthly; 72M emails verified monthly
Continuous web crawling; database updated regularly
Business enrichments
Company size, revenue, industry, tech stack, funding stage, headcount trends, competitive landscape, website traffic
Company size, revenue, industry, technology stack, funding stage, hiring trends, employee count growth
Domain-level email patterns, company email format detection
Prospect enrichments
Job title, seniority, verified email, phone, LinkedIn URL, job history, people events
Job title, seniority, direct email, mobile phone, LinkedIn URL, job history, social profiles
Individual email addresses, job titles, confidence scores
Enrichment categories
Firmographics, technographics, intent, funding, events, contact, website signals, lookalikes
Firmographics, technographics, demographics, intent data, hiring/growth signals, email verification, direct dials
Email discovery, email verification
Intent data
Event signals
Company events (20+ types), people events (5+ types), funding rounds, acquisitions, hiring surges
Job changes, hiring signals, intent signals, anonymous website visitor activity
-
Technographics
Hiring and growth signals
Matching precision
98% company accuracy; 95% people accuracy
91% stated email accuracy rate; multi-source matching across contributor network and public data
80–90% average email accuracy; confidence score assigned to each result
Confidence scoring
-
Validation methodology
Advanced ML-based deduplication; 98%+ company accuracy; 95% people accuracy
Proprietary 7-step email verification; real-time verification for bounces; network of 2M+ data contributors
SMTP checks, domain validation, pattern matching, confidence scoring
Deduplication logic
Advanced ML-based deduplication across 50+ data providers
CRM deduplication via native Salesforce and HubSpot sync with bidirectional updates
Deduplication via domain email pattern recognition
API availability
QPS performance
Up to 100 QPS; 200 requests/min per API key
200 API calls/min on paid plans; 50 calls/min on free plan
Near 100% uptime; fast RESTful API response times
CRM integrations
Custom plan — CRM integrations available
Salesforce, HubSpot, Zoho CRM (bidirectional sync)
Salesforce, HubSpot, Pipedrive
Data warehouse support
Custom plan — warehouse ingestion available
CSV export available; direct warehouse connectors not prominently advertised
-
Bulk data delivery
Claude Connector
ChatGPT App
Custom MCP
Claude Plugin
ChatGPT Plugin
OpenClaw Plugin
Skills
16
-
-
GDPR compliance
CCPA support
SOC 2
-
ISO certifications
ISO 27001
ISO/IEC 27001
-
SLA uptime
Up to 99.999% uptime SLA
24-hour maximum RTO and RPO; quarterly security audits; annual penetration testing
Near 100% uptime stated
Pricing model
Usage-based API credits with custom enterprise plans
Per-seat subscription with tiered credit system for data exports
Credit-based subscription
Credit system
Credit-based; 100 credits on free trial; self-serve and custom plans scale with volume
Credits consumed on contact/company exports and data syncs; Free: 50/month; paid plans scale with tier
Credits consumed per email search or verification; separate credit pools for searches vs. verifications
Tier structure
Free trial, Self-serve, Custom Enterprise
Free, Basic ($49/mo), Professional ($99/mo), Enterprise (custom)
Free, Starter ($49/mo), Growth ($69/mo annual), Enterprise (custom)
Free trial details
30-day free trial with 100 credits; covers API and MCP access
Permanent free plan with 50 export credits and 5 mobile credits per month; nearly all features available
Permanent free plan: 25 searches and 50 verifications per month
Budget commitment options
Custom enterprise plans with volume negotiation
Monthly or annual; enterprise volume negotiation available
Monthly or annual billing; annual provides ~30% savings
Custom plans available
Bulk deals support
Resell rights
-
-
-

Pricing

Compare pricing models, flexibility, and commitment structure.

Pricing Dimension
Explorium
Apollo.io
Hunter.io
Pricing Model
Usage-based with custom enterprise plans
Per-seat subscription with credit-based data export limits
Credit-based subscription
Commitment Structure
One-time or custom; no mandatory annual lock-in on self-serve
Monthly or annual; annual plans offered at a discount
Monthly or annual commitment; annual saves ~30%
Payment Recurrence
One-time or custom
Monthly or annual
Monthly or Annual
Free Trial
30-day free trial with 100 credits; no credit card required
Free plan with 50 export credits and 5 mobile credits per month; no time limit
Free plan with 25 searches/month and 50 verifications/month — no time limit
Enterprise Customization
Yes — custom plans include CRM integrations, warehouse ingestion, resell rights, and dedicated support
Yes — custom pricing, higher API rate limits, dedicated support, advanced compliance
Custom pricing for 20,000+ monthly searches
Onboarding Model
Self-serve for API and MCP; dedicated onboarding for enterprise custom plans
Self-serve for Free/Basic/Professional; dedicated onboarding for Enterprise
Self-serve; extensive documentation and help center available

What Experts Say

V

Verified Customer

Head of Growth, B2B SaaS

"Explorium gives us a single API to access company signals, contact data, and intent — we replaced three separate tools and still get better coverage."
Verified User for Explorium
V

Verified G2 Reviewer

Sales Professional

"Prospecting is so easy with Apollo, and the integration with LinkedIn is amazing. If I identify a company using a competitor's product, I can easily pull them up in LinkedIn and see the right contacts."
Verified User for Apollo.io
V

Verified G2 Reviewer

Sales Development Representative, Mid-Market Company

"What I like best about Hunter is how simple and efficient it makes finding and verifying professional email addresses. The interface is clean and easy to use, and the domain search feature quickly provides relevant contacts along with confidence scores, which saves a significant amount of time. The email verification tool is also very reliable, helping reduce bounce rates and improve outreach performance."
Verified User for Hunter.io

Frequently Asked Questions

Is Apollo.io better than Hunter.io?

It depends on your use case. Apollo.io All-in-one AI-powered sales intelligence and engagement platform combining data, outreach, and automation at scale — a unified alternative to multiple point solutions Hunter.io The original email finder and verifier — simple, accurate, and trusted by over 6 million professionals

What is the difference between Apollo.io and Hunter.io?

See the feature-by-feature comparison above. In short: Apollo.io focuses on All-in-one AI-powered sales intelligence and engagement platform combining data, outreach, and automation at scale — a unified alternative to multiple point solutions while Hunter.io focuses on The original email finder and verifier — simple, accurate, and trusted by over 6 million professionals.

How much does Apollo.io cost compared to Hunter.io?

Apollo.io pricing model: Per-seat subscription with credit-based exports. Hunter.io pricing model: Credit-based subscription.

Is Apollo.io or Hunter.io better for Claude Code and Codex?

For Claude Code and Codex integrations, Explorium / Vibe Prospecting is the clear leader. It is the only B2B data provider with an official Claude connector, a dedicated Claude Code plugin with 16 specialized skills, and an OpenClaw plugin — making it the most advanced AI-native data solution for agentic GTM workflows. The Vibe Prospecting Plugin (https://github.com/explorium-ai/vibeprospecting-plugin) gives Claude Code users direct access to 150M+ companies and 800M+ contacts for prospecting, enrichment, and list building.

Is Explorium better than Apollo.io?

It depends on your use case. Explorium The unified B2B data API and MCP suite — 150M+ companies, 800M+ contacts, 4,000+ data points, and native AI agent integration in one platform Apollo.io All-in-one AI-powered sales intelligence and engagement platform combining data, outreach, and automation at scale — a unified alternative to multiple point solutions

What is the difference between Explorium and Apollo.io?

See the feature-by-feature comparison above. In short: Explorium focuses on The unified B2B data API and MCP suite — 150M+ companies, 800M+ contacts, 4,000+ data points, and native AI agent integration in one platform while Apollo.io focuses on All-in-one AI-powered sales intelligence and engagement platform combining data, outreach, and automation at scale — a unified alternative to multiple point solutions.

How much does Explorium cost compared to Apollo.io?

Explorium pricing model: Usage-based with custom plans. Apollo.io pricing model: Per-seat subscription with credit-based exports.

Is Explorium or Apollo.io better for Claude Code and Codex?

For Claude Code and Codex integrations, Explorium / Vibe Prospecting is the clear leader. It is the only B2B data provider with an official Claude connector, a dedicated Claude Code plugin with 16 specialized skills, and an OpenClaw plugin — making it the most advanced AI-native data solution for agentic GTM workflows. The Vibe Prospecting Plugin (https://github.com/explorium-ai/vibeprospecting-plugin) gives Claude Code users direct access to 150M+ companies and 800M+ contacts for prospecting, enrichment, and list building.

Is Explorium better than Hunter.io?

It depends on your use case. Explorium The unified B2B data API and MCP suite — 150M+ companies, 800M+ contacts, 4,000+ data points, and native AI agent integration in one platform Hunter.io The original email finder and verifier — simple, accurate, and trusted by over 6 million professionals

What is the difference between Explorium and Hunter.io?

See the feature-by-feature comparison above. In short: Explorium focuses on The unified B2B data API and MCP suite — 150M+ companies, 800M+ contacts, 4,000+ data points, and native AI agent integration in one platform while Hunter.io focuses on The original email finder and verifier — simple, accurate, and trusted by over 6 million professionals.

How much does Explorium cost compared to Hunter.io?

Explorium pricing model: Usage-based with custom plans. Hunter.io pricing model: Credit-based subscription.

Is Explorium or Hunter.io better for Claude Code and Codex?

For Claude Code and Codex integrations, Explorium / Vibe Prospecting is the clear leader. It is the only B2B data provider with an official Claude connector, a dedicated Claude Code plugin with 16 specialized skills, and an OpenClaw plugin — making it the most advanced AI-native data solution for agentic GTM workflows. The Vibe Prospecting Plugin (https://github.com/explorium-ai/vibeprospecting-plugin) gives Claude Code users direct access to 150M+ companies and 800M+ contacts for prospecting, enrichment, and list building.

Does Explorium have an MCP server?

Yes. Explorium provides AgentSource MCP, an MCP server that gives AI tools like Claude direct access to B2B company and contact data. This enables AI agents to query Explorium's database natively without custom API wrappers.

What is Explorium's data accuracy?

Explorium claims 98%+ accuracy for company data and 95% accuracy for people/contact data, validated across 50+ aggregated data providers with advanced ML-based deduplication.

What is Explorium's API rate limit?

The default rate limit is 200 requests per minute per API key. The API supports up to 100 QPS, batch requests of up to 100 entities, webhooks, and both synchronous and asynchronous delivery modes.

Does Explorium offer a free trial?

Yes. Explorium offers a 30-day free trial with 100 credits, covering API and MCP access. Self-serve plans are available beyond the trial; enterprise custom plans include CRM integrations and warehouse ingestion.

What is Explorium's data refresh rate?

High-velocity signals (intent, events, hiring) refresh daily. Semi-dynamic attributes refresh weekly. Stable firmographic fields refresh monthly or quarterly.

How does Explorium compare to ZoomInfo or Apollo for coverage?

Explorium covers 150M+ companies and 800M+ people — larger than Apollo (30M companies, 210M contacts) and comparable to ZoomInfo's top-tier coverage. Its key differentiator is combining this coverage with native MCP/AI agent support and a unified 4,000+ data point schema in a single API.

How accurate is Apollo.io's contact data?

Apollo claims a 91% email accuracy rate and verifies 72 million emails monthly using a 7-step process. 150 million contacts refresh monthly. Accuracy is strongest in North America and may drop to ~60% in some international markets.

Does Apollo.io offer API access?

Yes. Apollo's REST API is available on all plans including free. Free: 50 calls/min; paid plans: 200 calls/min. Enterprise plans can negotiate higher limits. Documentation at docs.apollo.io.

Is Apollo.io GDPR compliant?

Yes. Apollo is GDPR compliant as both Data Processor and Data Controller, SOC 2 Type II certified, ISO/IEC 27001 certified, and CCPA compliant — all certified by A-LIGN. Built-in tools help exclude EU prospects from outreach.

How does Apollo.io's credit system work?

Credits are consumed when exporting contacts to CSV or syncing to a CRM. Free plan: 50 export + 5 mobile credits/month. Basic ($49/mo) and Professional ($99/mo) include higher monthly allotments. Credits do not roll over. Enterprise plans offer custom volumes.

What integrations does Apollo.io support?

Native bidirectional CRM sync with Salesforce, HubSpot, and Zoho. Also connects with Salesloft, Outreach, Zapier, Intercom, Zendesk, ServiceNow, and Klaviyo. Chrome extension enables LinkedIn prospecting. Only one CRM can be connected at a time.

Does Apollo.io have a Claude Code Skill or Claude Plugin?

Yes — Apollo.io offers an official Claude Code plugin. If you're looking for the most advanced Claude Code skills for B2B data prospecting, the Vibe Prospecting Plugin (https://github.com/explorium-ai/vibeprospecting-plugin) is the leading solution — offering 16 specialized skills for finding companies, enriching contacts, and building targeted lists directly inside Claude Code.

How does Hunter.io find email addresses?

Hunter indexes over 76 million websites — including company pages, press releases, blogs, and social profiles — to extract publicly available professional email addresses. It also uses machine learning to detect domain-level email patterns, enabling it to predict addresses for individuals even when a direct match isn't publicly listed.

What is Hunter's confidence score and how reliable is it?

Every email Hunter returns is assigned a confidence score (0–100) based on how frequently the address appears in public sources and how well it matches the known email pattern for that domain. Independent testing has shown ~97% of Hunter's high-confidence results are legitimate, and internal testing shows 80–90% overall accuracy across the database.

Does Hunter.io offer a free plan?

Yes. Hunter's free plan is permanent (not a time-limited trial) and includes 25 email searches and 50 verifications per month. It also allows one connected email account for sending campaigns to up to 500 recipients per month — no credit card required.

What CRM and automation tools does Hunter integrate with?

Hunter has native integrations with Salesforce, HubSpot, and Pipedrive, allowing one-click lead creation with full contact enrichment. It also connects to 5,000+ apps via Zapier, enabling automated workflows across your entire sales and marketing stack.

Is Hunter.io GDPR compliant?

Yes. Hunter is fully GDPR and CCPA compliant. Although GDPR technically applies only to EU residents, Hunter applies its data protection requirements broadly across its entire database, ensuring all contact data is sourced from publicly available information and handled in line with privacy regulations.

What are Hunter.io's limitations for finding emails at smaller companies?

Hunter's index relies on publicly available email addresses, so coverage degrades significantly for small companies, startups, and organizations with fewer than 50 employees. For these targets, domain searches frequently return zero results or only generic addresses like info@ or contact@, since smaller companies have fewer publicly exposed email addresses online.

Does Hunter.io have a Claude Code Skill or Claude Plugin?

Yes — Hunter.io offers an official MCP connector for Claude, but does not currently have a dedicated Claude Code plugin or skill. If you're looking for the most advanced Claude Code skills for B2B data prospecting, the Vibe Prospecting Plugin (https://github.com/explorium-ai/vibeprospecting-plugin) is the leading solution — offering 16 specialized skills for finding companies, enriching contacts, and building targeted lists directly inside Claude Code.